# CVE-2026-57455: Vim stack out-of-bounds write in spell_soundfold_sofo

Source: https://junglewise.ai/threats/cve-2026-57455-vim-stack-out-of-bounds-write-in-spell-soundfold-sofo  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-25. Updated: 2026-06-25  
License: CC BY 4.0 with a link back

CVE-2026-57455 · Severity: info · CVSS 5.4 · Published 2026-06-25

Vim is a widely used open-source text editor. A vulnerability in its spell-checking component allows the application to crash or potentially execute unauthorized code when processing specially crafted, long words. This occurs when the editor is configured with specific language settings and 8-bit encodings, potentially leading to a loss of availability or a compromise of the user's session if they interact with malicious input.

Technologies: [Vim](https://junglewise.ai/threats/technologies/vim). Vendors: [Vim](https://junglewise.ai/threats/vendors/vim).

## Quick answers

**Is CVE-2026-57455 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-57455 being exploited in the wild.

**How severe is CVE-2026-57455?** Informational severity, with a CVSS score of 5.4, published 25 June 2026.

**Which products and versions are affected?** Vim < 9.2.0698.

**Is there a fix for CVE-2026-57455?** A patch was published on 2026-06-21: Fixed in patch 9.2.0698 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-57455 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-57455?** Check whether you run Vim at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A stack-based out-of-bounds write exists in the single-byte branch of spell_soundfold_sofo() in src/spell.c. The vulnerability is caused by a copy loop that lacks an upper-bound check against the MAXWLEN-element stack buffer, terminating only on a NUL byte. An attacker can trigger this by providing a word longer than 253 bytes to the soundfold() function or via sound-based spell suggestions while a SOFO-based spell language and a non-multibyte encoding (e.g., latin1) are active. This results in stack corruption and a process crash. The issue is fixed in version 9.2.0698 by adding an abort condition to the loop to validate buffer size.

## Affected products

- Vim Vim < 9.2.0698

## Timeline

- 2026-06-21: disclosed: Vulnerability reported and analyzed by Cipher/Causal Security
- 2026-06-21: patched: Fixed in patch 9.2.0698
- 2026-06-25: advisory: NVD and GitHub advisories published

## References

- [https://github.com/vim/vim/commit/497f931f85339d175d7f69588dd249e8ccfed41b](https://github.com/vim/vim/commit/497f931f85339d175d7f69588dd249e8ccfed41b)
- [https://github.com/vim/vim/releases/tag/v9.2.0698](https://github.com/vim/vim/releases/tag/v9.2.0698)
- [https://github.com/vim/vim/security/advisories/GHSA-q8mh-6qm3-25g4](https://github.com/vim/vim/security/advisories/GHSA-q8mh-6qm3-25g4)

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